Objective: Ou MC decrescendo phenomenon (OuDP) is produced by placing the contralateral hand over a diseased location to produce a zone under the hand with decreased pain or inflammation [1]. Our objective is to understand the possible mechanism of OuDP. Methods: OuDP can be induced by the patients themselves or the therapist [1] by placing the contralateral hand directly on the affected area. During 2012-2015, 147 patients with various diseases were treated with OuDP. In these patients, 56 patients was treated with both ipsilateral and contralateral hand to induce OuDP [2-5]. Though complementary therapy is exempt from informed consent by the law in Taiwan (Department Health, ROC, 1993, No.82075656), all patients agreed and provided consent for participation in this study. Results: The 56 patients treated with contralateral and ipsilateral hand showed that application with contralateral hand resulted in OuDP for all the patients, while the ipsilateral hand resulted in OuDP for only one patient (1/56, 2.0%)—Difference between contralateral and ipsilateral hand to induce OuDP, P < 0.001, Paired t test. The OuDP showed effect of remission or cure for the diseases or relief of clinical symptoms in 144 of the 147 patients (98.0%). (Table 1) Conclusions: The Ou HR appears to be consistently effective for treating a wide variety of diseases, such as infections, inflammation, degenerative diseases, organ dysfunction, and malignant oncologic changes, Embryological development of animals usually patterns along the embryonic axes with regard to the functional features developed during early embryonic life. Recent studies have shown the signaling system of embryonic axes imparts polarization of individual cells leading to normal function. Most human cells and tissue in adults are polarized to have normal functions. OuDP can be effectively induced with the contralateral hand, but not the ipsilateral hand, which implies that the axes of embryonic polarity, especially the left-right axis, are the potential mechanism underlying the OuDP (Figure 1). Linguistic studies have demonstrated that a space-time congruency effect exists from the left to right that is coordinated with the left-right axis of the human body. This indicates there are mutual interactions of the left to right axis between individuals that may result in a physiological response..